The present invention relates to a skywriting apparatus and especially to a skywriting apparatus for simultaneously releasing a plurality of vapor streams or puffs in a predetermined pattern to form an aerial message with one pass of the airplane.
In the past, skywriting has been employed by a variety of means, including having vapor or smoke generators attached to a plane and have the plane fly a predetermined pattern as the pilot released smoke or vapor to form the message in the pattern that the pilot was flying. This method, however, required a substantial amount of flying time for the pilot in precision patterns to gradually put the letters together in smoke while releasing the smoke at only predetermined points. Typical devices for creating smoke in this manner may be seen in the Haddock, et al., U.S. Pat. No. 2,062,511. The smoke or vapor may be generated in a variety of ways including the injection of foil into the exhaust of the airplane for generating the vapor as illustrated in the Haddock patent, the injection of oil on a hot plate in an exhaust pipe section as illustrated in the Rankin U.S. Pat. No. 2,404,812; the production of smoke or fog in a burner such as in the Durr, et al., U.S. Pat. No. 3,244,641; and in a smoke generator such as in U.S. Pat. No. 3,632,067 and in the multiple smoke signal unit of U.S. Pat. No. 2,945,222. Signals are also generated by the use of chemicals such as titanium tetrachloride, which hydrolyzes upon coming into contact with the moisture in the air to form a white cloud such as shown in the Remey U.S. Pat. No. 2,065,024. There have been a number of suggestions for simplifying skywriting by avoiding the aerobatics required in forming the message along the pattern being flown by the airplane. These include the Hineman Pat. No. 1,503,830, for a skywriting device which releases bombs on a remote control pattern, which are ignited in a predetermined pattern to form the wording of the message. The Remey U.S. Pat. No. 2,065,024 and the Copeland U.S. Pat. No. 3,089,271, each teaches columns which extend from and below an air plane which may be released from the airplane on a winch and drawn back onto the winch. Each column has a pair of pipes formed therein and to which a plurality of spaced nozzles are connected so that the fluid from each column can be released from a remote command by actuating a nozzle to release the chemicals. Typically, titanium tetrachloride is used to produce a chemical smoke trail when released by a valve. The column in the Remey patent has stabilizer fins to stabilize the extended column below the plane. The Copeland patent also reaches a "piano roll" type control for controlling the release of the chemicals in a predetermined pattern, and includes the use of a winch along with controlling rollers and a guide drum for releasing and retracting the signal column and a terminating weight to help straighten the pipe line for generating the signal. The Remey patent on the other hand, does not provide for the extension and retraction of the column with the fins and nozzles protruding therefrom. In one prior U.S. Pat. No. 2,308,060, to DeRochefort-Lucay, a Means for producing Signs in Space, is provided which places a plurality of signal generators along the top of the airplane wing and controls the release of the smoke in a piano roll-type mechanism, actuating the valves in the order of the pattern on the attached roll.
The present invention advantageously provides for a long column to extend from the airplane supported from a standard winch cable while using a separate cable to space the vapor generator units. Each vapor generator is therefore attached to a steel cable and includes its own stabilizer tail and individual burner which can be ignited from the plane and an oil injection unit which is remotely controlled from the plane responsive to a remot control unit, the remote control unit provides for a quick change of messages which can be quickly produced on a film strip for writing the message in one pass of the airplane.